Boosted by its stellar cast and playful take on “A Christmas Carol,” “The Night Before” is a stoner buddy comedy laced with holiday cheer.

Make no mistake: It’s still a silly romp, thick with dope smoke and dumb jokes. But the performances are solid, and there’s some surprising sentiment behind the wacky antics.

Joseph Gordon-Levitt, Seth Rogen and Anthony Mackie play best friends bidding farewell to their 10-year tradition of partying together on Christmas Eve. Ethan (Gordon-Levitt) is determined to make this last night an epic one — especially since Chris (Mackie) is on a hot streak in his football career and Isaac (Rogen) is expecting a baby.

Isaac’s wife, Betsy (the hilarious Jillian Bell), gives her husband a special gift in honor of the last Christmas Eve with his pals — a box filled with “every single drug in the whole world.”

Well, you can imagine how things go from there. Isaac dips into the stash as soon as they leave the house. Rogen is predictably over the top as he samples each substance, falling deeper and deeper into a delusional haze. This presents ample opportunity for gross-out moments, like when he barfs in church or lets his nose bleed into a woman’s martini.

Meanwhile, Ethan surprises his friends with tickets to the hottest party in town, the one they’ve dreamed of getting into since their holiday tradition began. But first, Chris needs to pick up some weed. (Somehow, Betsy left that out of the box.)

This sets the trio on their adventure, bringing them into contact with the mysterious Mr. Green (a brilliant Michael Shannon) for the first of several meetings. He introduces Chris to “the weed of Christmas present.” Later in the film, the weed of Christmas past and Christmas future is smoked, too. (Poor Dickens.)

Along the way, the guys meet up with Ethan’s ex-girlfriend (Lizzy Caplan) and her friend (Mindy Kaling), Chris’ mom (Lorraine Toussaint) and Rebecca Grinch (Ilana Glazer). The appearance of each actress is a little holiday treat that helps balance the dumb-guy debauchery. Miley Cyrus, James Franco and Tracy Morgan also do well-played cameos.

Isaac maintains a steady level of wasted-ness throughout the film as he frets about fatherhood. Rogen channels this with ease and with considerably more maturity than he did in 2007’s “Knocked Up.”

Chris documents his every move for his social media profile, but secretly feels his popularity may be coming at too high a price. With his Juilliard pedigree and dramatic gravitas, Mackie has poise and charisma to spare, so it’s oddly comic to hear him utter such lines as, “I just fame-(expletive) that hipster chick!”

Gordon-Levitt brings his usual charm and accessibility to Ethan, who faces the hardest holiday challenge: What will Christmas Eve be like without his buddies? They’ve moved on with their lives; why hasn’t he?

Written and directed by Jonathan Levine (“50/50,” “The Wackness”), “The Night Before” is a millennial story cloaked in a cloud of smoke. It’s a druggie comedy, to be sure, but a sweetness about vulnerability, honesty, friends and family helps cut through the haze.

Things may be tied up a little too neatly, but it is Christmas, after all.

Boosted by its stellar cast and playful take on “A Christmas Carol,” “The Night Before” is a stoner buddy comedy laced with holiday cheer.

Make no mistake: It’s still a silly romp, thick with dope smoke and dumb jokes. But the performances are solid, and there’s some surprising sentiment behind the wacky antics.

Joseph Gordon-Levitt, Seth Rogen and Anthony Mackie play best friends bidding farewell to their 10-year tradition of partying together on Christmas Eve. Ethan (Gordon-Levitt) is determined to make this last night an epic one — especially since Chris (Mackie) is on a hot streak in his football career and Isaac (Rogen) is expecting a baby.

Isaac’s wife, Betsy (the hilarious Jillian Bell), gives her husband a special gift in honor of the last Christmas Eve with his pals — a box filled with “every single drug in the whole world.”

Well, you can imagine how things go from there. Isaac dips into the stash as soon as they leave the house. Rogen is predictably over the top as he samples each substance, falling deeper and deeper into a delusional haze. This presents ample opportunity for gross-out moments, like when he barfs in church or lets his nose bleed into a woman’s martini.

Meanwhile, Ethan surprises his friends with tickets to the hottest party in town, the one they’ve dreamed of getting into since their holiday tradition began. But first, Chris needs to pick up some weed. (Somehow, Betsy left that out of the box.)

This sets the trio on their adventure, bringing them into contact with the mysterious Mr. Green (a brilliant Michael Shannon) for the first of several meetings. He introduces Chris to “the weed of Christmas present.” Later in the film, the weed of Christmas past and Christmas future is smoked, too. (Poor Dickens.)

Along the way, the guys meet up with Ethan’s ex-girlfriend (Lizzy Caplan) and her friend (Mindy Kaling), Chris’ mom (Lorraine Toussaint) and Rebecca Grinch (Ilana Glazer). The appearance of each actress is a little holiday treat that helps balance the dumb-guy debauchery. Miley Cyrus, James Franco and Tracy Morgan also do well-played cameos.

Isaac maintains a steady level of wasted-ness throughout the film as he frets about fatherhood. Rogen channels this with ease and with considerably more maturity than he did in 2007’s “Knocked Up.”

Chris documents his every move for his social media profile, but secretly feels his popularity may be coming at too high a price. With his Juilliard pedigree and dramatic gravitas, Mackie has poise and charisma to spare, so it’s oddly comic to hear him utter such lines as, “I just fame-(expletive) that hipster chick!”

Gordon-Levitt brings his usual charm and accessibility to Ethan, who faces the hardest holiday challenge: What will Christmas Eve be like without his buddies? They’ve moved on with their lives; why hasn’t he?

Written and directed by Jonathan Levine (“50/50,” “The Wackness”), “The Night Before” is a millennial story cloaked in a cloud of smoke. It’s a druggie comedy, to be sure, but a sweetness about vulnerability, honesty, friends and family helps cut through the haze.

Things may be tied up a little too neatly, but it is Christmas, after all.